AppImage support

[shuvashish76]

Request to add AppImage package available for linux users.
Unlike other packages AppImage is a community project & you could install without the need for a centralized store.
The use-case is same as Windows portable version.

Then maybe publish at https://www.appimagehub.com (more about it at ¹, ², ³) or get listed at https://appimage.github.io/apps/

Footnotes

1. https://en.wikipedia.org/wiki/OpenDesktop.org ↩

2. https://www.opendesktop.org/about ↩

3. https://www.pling.com/faq-pling ↩